The car is a 2016 subaru legacy. I need to remove the side area next to the gas pedal near my heel to create more room for my foot since the side area is blocking me from getting more then half my foot on the gas pedal and creates an awkward amount of pressure which makes tendinitis flare up in my foot. I explain in this video I made showing the area that needs modifying. https://www.youtube.com/watch?v=K9n37yz6sHw&feature=youtu.be
What is under the felt in that area, and what is involved in removing it and putting the felt back on?

I guess you did purchase your friends Subaru to solve your brake pedal problem. I think you will need to have a body shop solve this for you. There will be metal to cut and something welded back in place.

It would be easier to remove the gas pedal assembly, slip the rubber pad off the pedal plate, cut the pedal plate off the bar, shift the pedal plate slightly to left, and weld it back onto the bar, and reinstall rubber pad back onto the plate.

You might be lucky enough that there is enough slop in the pedal mounting holes to loosen the bolts and then move the pedal into a position that works for you. Using a slightly larger drill bit to enlarge the holes can give a bit more. A small movement at the mounting hole grows to quite a bit at the pedal itself.

Matt started in April asking about left foot accelerator modification. He needs a brake pedal that does not hurt his leg. Now he says he needs more room for his foot. In 7 months why has he not looked for a vehicle that he could use or contacted a handicap vehicle adaption shop.